The Grade II-listed building, completed in 1894, was the seat of the Windsor-Clive family - originally given the estate by Henry VIII - until they sold it to the state, which turned it into a borstal in 1946. The prison has a farm and gardens, also Grade II listed, where inmates work.

Last night it was also claimed that spaces at another jail remained unused because its kitchen could not provide a choice of meals.

As prisoner numbers hit a record high yesterday, an officers' leader claimed that there were up to 292 wasted beds at HMP Birmingham.

A multi-million pound expansion project has increased the jail's capacity, but because the kitchen is not big enough to give prisoners a choice of meals - including vegetarian and specific diet requirements - it will not fill the cells, he claimed.

Brian Clarke, the chairman of Birmingham's Prison Officers' Association, said: "We could accommodate an extra 292 prisoners, we have those extra beds. We need a bigger kitchen and more staff."

The disclosures emerged after a prison officers' leader said jails had become so comfortable that some inmates were ignoring chances to escape. Further details of luxuries emerged yesterday.

At Hewell Grange, an open prison in Redditch, Worcs, inmates can use a bowling green in the summer at the Grade II, 19th century property, built by the Earl of Plymouth as a family home.

Facilities inside the marble-floored house with oak panelled walls include a gym, a snooker room and a library where inmates can borrow CDs and computer games. Each dormitory - there are no cells - has its own television. One inmate serving a 15-year sentence for kidnap said the facility was "like a hotel, except it's free".

The Prison Service disclosed that the number of inmates in England and Wales had reached a new high of 82,319.

Magistrates have been urged by Jack Straw, the Justice Secretary, to reduce the number of criminals they sent to jail, in a fresh bid to ease prison overcrowding.

The former Home Office minister Ann Widdecombe said prisoners were left to be "idle" and should be given work to do to keep them busy.

"Every single convicted prisoner should have to do a full day's work either in the prison workshop or education department or a mixture of both," she said. "Because they are idle, prisoners have more opportunities for drug dealing."

The Ministry of Justice yesterday denied that there were free spaces at Birmingham and said it was at its full operational capacity.